Question 1

Tropical marine waters have the highest rate of primary productivity in the world's oceans.

Accepted Answer

Tropical marine waters generally have lower primary productivity compared to temperate and polar regions due to nutrient limitations, despite having abundant sunlight.

Question 2

Equatorial upwelling decreases primary production in tropical waters.

Accepted Answer

Equatorial upwelling increases primary production in tropical waters by bringing nutrient-rich deep waters to the surface, which supports the growth of phytoplankton.

Question 3

The group of marine algae with the highest abundance and greatest geographic distribution belong to the Division Rhodophyta.

Accepted Answer

This statement is true. The Division Rhodophyta, also known as red algae, have the highest abundance and greatest geographic distribution among marine algae. They are found in all oceans and at all depths, from the Arctic to the tropics.

Question 4

Nitrogen and phosphorus concentrations have no impact on primary productivity rates in marine ecosystems.

Accepted Answer

Nitrogen and phosphorus are essential nutrients for primary productivity in marine ecosystems, as they are limiting factors for the growth of phytoplankton and other primary producers. Higher concentrations of these nutrients can lead to increased primary productivity rates.

Question 5

Diatoms are classified as members of the Division Chlorophyta.

Accepted Answer

Diatoms are actually classified as members of the Division Bacillariophyta. Chlorophyta is the division for green algae.

Question 6

Primary productivity in temperate marine systems is limited by the amount of available solar radiation.

Accepted Answer

Primary productivity in temperate marine systems is often limited by nutrients, such as nitrogen and phosphorus, rather than solar radiation, which is more abundant in these regions.

Question 7

Bacteria that manufacture carbohydrates in the absence of solar energy from inorganic carbon are autotrophs.

Accepted Answer

Autotrophs are organisms that can manufacture their own organic compounds like carbohydrates from inorganic sources like carbon dioxide, without the need for external energy sources such as sunlight. Bacteria that can do this are called chemoautotrophs, and they can be found in environments such as deep-sea hydrothermal vents or underground caves where sunlight is not available.

Question 8

Marine algae that grow close to the limits of light penetration have accessory photosynthetic pigments that absorb high energy, short-wavelength light in the blue region of the electromagnetic spectrum.

Accepted Answer

Marine algae that grow close to the limits of light penetration have accessory pigments like fucoxanthin that absorb high energy blue light in addition to chlorophyll a to maximize their photosynthetic efficiency.

Question 9

Most marine algae are limited to depths above 100 meters; red algae have been observed growing at depths of over 250 meters.

Accepted Answer

Red algae have specialized pigments that allow them to photosynthesize in low-light conditions, enabling them to grow at greater depths than most other marine algae.

Question 10

Consumers, producers, and decomposers are all examples of trophic levels within a food chain or food web.

Accepted Answer

Trophic levels refer to the hierarchical levels in an ecosystem, and consumers, producers, and decomposers are all examples of different trophic levels within a food chain or food web. Consumers obtain energy by consuming other organisms, producers convert energy from the sun into food, and decomposers break down dead organic matter and recycle nutrients back into the ecosystem.

Question 11

If the total caloric content of the autotrophic organisms in a marine ecosystem were 250,000 KCAL, then the expected caloric value for the second-level consumers would be 25,000 KCAL.

Accepted Answer

The expected caloric value for second-level consumers is only 10% of the caloric content of the autotrophic organisms, which would be 25,000 KCAL. Therefore, the statement is false. The correct answer would be 25,000 KCAL.

Question 12

An overabundance of organic matter results in eutrophication.

Accepted Answer

The answer of An overabundance of organic matter results in...

Question 13

The by-products of photosynthesis are carbon dioxide (CO₂) and water (H₂O).

Accepted Answer

The by-products of photosynthesis are actually oxygen (O₂) and water (H₂O), not carbon dioxide and water.

Question 14

Energy flow is unidirectional in contrast to nutrients, which cycle in ecosystems.

Accepted Answer

Energy flows through ecosystems in a unidirectional manner, from the sun (or other energy source) to producers, then to consumers, and ultimately to decomposers, where it is lost as heat. Nutrients, on the other hand, cycle within ecosystems as they are taken up by organisms, recycled through decomposition, and released back into the environment for reuse.

Question 15

The amount of carbon dioxide concentrations and available nutrients affect the rate of primary production in an ecosystem.

Accepted Answer

Carbon dioxide is a major component of photosynthesis, which drives primary production. Nutrients such as nitrogen and phosphorus also play a crucial role in primary production, as they are needed for the growth and development of plant and algal cells. Therefore, the availability of both carbon dioxide and nutrients can significantly impact the rate of primary production in an ecosystem.

Question 16

Net primary production can be estimated as the amount of photosynthesis plus the amount of respiration.

Accepted Answer

Net primary production is calculated by subtracting the amount of energy used in plant respiration from the amount of photosynthesis. Therefore, net primary production is the amount of organic matter or biomass that is produced by a plant community or ecosystem.

Question 17

Compensation depth is the depth in the ocean where the photosynthetic rates exceeds the rate of cellular respiration.

Accepted Answer

Compensation depth is the depth in the ocean where the rate of photosynthesis equals the rate of cellular respiration, not exceeds it.

Question 18

The depth at which the cellular respiration rate equals the photosynthetic rate is referred to as the:

Accepted Answer

The depth at which the cellular respiration rate equals the photosynthetic rate is referred to as the oxygen compensation depth. This is because at this depth, the amount of oxygen produced by photosynthesis is just enough to balance out the amount of oxygen consumed during cellular respiration.

Question 19

Diatoms, important producers in the epipelagic open ocean, are members of the Division:

Accepted Answer

The answer of Diatoms, important producers in the epipelagic open...

Question 20

In temperate oceans during the summer months:

Accepted Answer

The answer of In temperate oceans during the summer months:
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Quiz 13: Biological Productivity and Energy Transfer